It uses in the development of industrial engines.
In the engine of the motor vehicle manufacturers, there is a place you are using a bolt of 12 corners in the 12 ~ 17mm.
You use at that time.
Because the hardware store or the like do not put the 12 corners of the manufacturers product, we used reluctantly the 12 square socket of inexpensive box wrench set.
This time, I bought there is yet posted made KTC of 12 corners in Monotarou's.
12.7 so you can also use the torque wrench of 1800N · m.